AVPlayer已取消分配，而键值观察者仍在其中注册 [英] AVPlayer was deallocated while key value observers were still registered with it

问题描述

我正在创建一个简单的媒体播放器应用。我的应用程序在播放第一个链接时崩溃，我点击了uitableview中的第二个链接。

I am creating a simple media player app. My App is crashed when first link is played and I clicked second link in uitableview.

- (void)viewDidLoad {
        [super viewDidLoad];
        arrURL = [NSArray arrayWithObjects: @"http://yp.shoutcast.com/sbin/tunein-station.pls?id=148820", @"http://www.kcrw.com/pls/kcrwmusic.pls",@"http://yp.shoutcast.com/sbin/tunein-station.pls?id=175821",@"http://yp.shoutcast.com/sbin/tunein-station.pls?id=148820",@"http://yp.shoutcast.com/sbin/tunein-station.pls?id=70931",nil];
        url = [[NSURL alloc] init];    
    }

    - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

        return [arrURL count];
    }

- (UITableViewCell *)tableView:(UITableView *)tableView
         cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *MyIdentifier = @"MyIdentifier";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
    if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:MyIdentifier] ;
    }
     cell.textLabel.text = [arrURL objectAtIndex:indexPath.row];
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    selectedSongIndex = indexPath.row;
    url = [[NSURL alloc] initWithString:[arrURL objectAtIndex:indexPath.row]];
    [self setupAVPlayerForURL:url];
    [player play];

    //[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
- (IBAction)btnPlay_Click:(id)sender {

    [player play];
    AVPlayerItem *item = player.currentItem;
    [item addObserver:self forKeyPath:@"timedMetadata" options:NSKeyValueObservingOptionInitial| NSKeyValueObservingOptionNew| NSKeyValueObservingOptionOld| NSKeyValueObservingOptionPrior context:nil];
}
- (IBAction)btnPause_Click:(id)sender {

    [player pause];
}

- (IBAction)btnStop_Click:(id)sender {

    [player pause];
}
-(void) setupAVPlayerForURL: (NSURL*) url1 {
    AVAsset *asset = [AVURLAsset URLAssetWithURL:url1 options:nil];
    AVPlayerItem *anItem = [AVPlayerItem playerItemWithAsset:asset];

    player = [AVPlayer playerWithPlayerItem:anItem]; **//Application Crashed**
    [player addObserver:self forKeyPath:@"status" options:0 context:nil];
}
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    if([keyPath isEqualToString:@"timedMetadata"])
    {
        AVPlayerItem *item = (AVPlayerItem *)object;
        NSLog(@"Item.timedMetadata: %@",item.timedMetadata);
        NSLog(@"-- META DATA ---");
        //        AVPlayerItem *pItem = (AVPlayerItem *)object;
        for (AVMetadataItem *metaItem in item.timedMetadata) {
            NSLog(@"meta data = %@",[metaItem commonKey]);
            NSString *key = [metaItem commonKey]; //key = publisher , key = title
            NSString *value = [metaItem stringValue];
            NSLog(@"key = %@, value = %@", key, value);
            if([[metaItem commonKey] isEqualToString:@"title"])
            {
                self.lblTitle.text = [metaItem stringValue];
            }
        }
    }
    if (object == player && [keyPath isEqualToString:@"status"]) {
        if (player.status == AVPlayerStatusFailed) {
            NSLog(@"AVPlayer Failed");
        } else if (player.status == AVPlayerStatusReadyToPlay) {
            NSLog(@"AVPlayer Ready to Play");
        } else if (player.status == AVPlayerItemStatusUnknown) {
            NSLog(@"AVPlayer Unknown");
        }
    }
}

我在App时收到此消息崩溃。

I got this message when App crashed.

***由于未捕获的异常'NSInternalInconsistencyException'而终止应用程序，原因：'
类AVPlayer的实例0x165297c0被解除分配，而关键价值观察员仍在其中注册了
。当前观察信息：
（上下文：0x0，属性：0x1661d5d0>）'

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'An instance 0x165297c0 of class AVPlayer was deallocated while key value observers were still registered with it. Current observation info: ( Context: 0x0, Property: 0x1661d5d0> )'

应用程序仅在IOS中崩溃IOS 7中的8工作正常。
我做错了什么？

Application crashed only in IOS 8 in IOS 7 works fine. What I am doing wrong??

推荐答案

我有一个类似的问题。它在iOS 7中运行良好，现在它在iOS 8中崩溃。

I had a similar problem. It worked fine in iOS 7, and now it crashes in iOS 8.

解决方案是在释放对象之前移除观察者。

The solution was to remove the observer, before releasing the object.

当您为成员替换或分配新对象时，您将释放旧对象，因此您需要先删除观察者：

When you replace or allocate a new object for a member, you're releasing the old object, so you need to remove the observer first :

-(void) setupAVPlayerForURL: (NSURL*) url1 {
    AVAsset *asset = [AVURLAsset URLAssetWithURL:url1 options:nil];
    AVPlayerItem *anItem = [AVPlayerItem playerItemWithAsset:asset];
    if (player != nil)
        [player removeObserver:self forKeyPath:@"status"];
    player = [AVPlayer playerWithPlayerItem:anItem]; 
    [player addObserver:self forKeyPath:@"status" options:0 context:nil];
}

同样在btnPlayClick中（如果在没有按下btnStop_Click的情况下按下它）：

And similarly in btnPlayClick ( in case it is pressed without btnStop_Click being pressed) :

- (IBAction)btnPlay_Click:(id)sender {
     if (player != nil && [player currentItem] != nil)
         [[player currentItem] removeObserver:self forKeyPath:@"timedMetadata"];
    AVPlayerItem *item = player.currentItem;
    [item addObserver:self forKeyPath:@"timedMetadata" options:NSKeyValueObservingOptionInitial|     NSKeyValueObservingOptionNew| NSKeyValueObservingOptionOld| NSKeyValueObservingOptionPrior context:nil];
    [player play];
}

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